Statistically speaking, Earthquakes forward Chris Wondolowski heads into Seattle on a customary tear. He has needed only three MLS matches to score three goals.

But Wondolowski is sounding like a guy in a slump as the Quakes head into Saturday’s Western Conference showdown in the Emerald City. He scored twice in a 3-0 road win over Toronto FC last week but could have had three or four scores. A few other chances also went by in a 1-0 loss to Houston.

“To be honest, I’ve gotten three goals, but I don’t think I’ve been sharp,” he said. “It’s kind of a funny thing being a striker — I scored two goals (against Toronto), but that was one of my worst games in awhile.”

The Sounders (2-0) know better than to expect a subpar showing from Wondolowski. The 2010 MLS Golden Boot Award winner has three goals in six career meetings against Seattle.

Wondolowski calls the game a “great litmus test.”

It’s a chance for the Quakes (2-1), who missed the playoffs last year, to show how far they’ve progressed, playing in a hostile environment against last year’s Western Conference runner-up. Wondolowski cites his team’s improved versatility, depth and variety of ways it can break down opponents. No matter his form, he’s been getting great service.

And there’s the mental side.

“We really have that confidence now where we can see games out,” Wondolowski said. “Last year, it was almost waiting for something to happen. You have so many things that go wrong throughout the whole season, and you’re waiting for that. This year we’re going to make our own luck.”

No doubt, the positives are adding up quickly. With a commanding back four of Honduran Victor Bernardez, Justin Morrow, Ramiro Corrales and Steven Beitashour, the Quakes have allowed no goals in the run of play and very few chances. Jon Busch worked his 62nd career shutout against Toronto FC. Shea Salinas, a huge addition to the attack this season, scored his first goal. Unsung Sam Cronin had two assists and was disruptive on defense.

One injury scare for the Quakes looks to have been dodged. After suffering a concussion against Toronto, midfielder Marvin Chavez is probable for Saturday’s game after being listed as questionable earlier in the week.

Chavez, who has 23 caps with the Honduran national team, passed his impact test with the league on Monday.

“I thought he ran around real well once we got the ball on the break against Toronto,” Yallop said. “He’s a gamer. He knows the game. He knows when to really burst and go, and he works hard for the team, which is a big, big part of it, as well.”

Meanwhile, the Sounders boast upstart forward David Estrada of Salinas, a former UCLA star who has a league-leading four goals in two matches.

Estrada’s emergence has a certain Wondolowski quality to it. He burst onto the scene with a hat trick in Seattle’s 3-1 season-opening win over visiting Toronto FC, scoring the first three goals of his three-year MLS career. He also struck in a 2-0 win over Houston.

“He’s got a ways to go before he does what Chris has done, but he’s had a great start, a fantastic start,” Yallop said of Estrada. “We’ve got to be really aware of him. He thinks he’s going to score every game he plays. Fredy Montero is not bad, either. They have a good team.”